Nematic liquid crystal composition and liquid crystal display device including the same

Abstract

Provided are a liquid crystal composition containing a compound represented by general formula (I-IV): and a compound represented by general formula (I): and a liquid crystal display device including the liquid crystal composition. The liquid crystal composition according to the present invention has a sufficiently low viscosity (η), a sufficiently low rotational viscosity (γ1), a high elastic constant (K 33 ), a high voltage holding ratio after UV exposure (VHR(UV)), and a large absolute value of negative dielectric anisotropy (Δ∈) without decreased refractive index anisotropy (Δn) or nematic-isotropic liquid phase transition temperature (T ni ). The display device including the liquid crystal composition has fast response time and good display quality with reduced or no display defects.

1 . A liquid crystal composition comprising:
 one or more compounds represented by general formula (I-IV):   
       
         
           
           
               
               
           
         
       
       (wherein R IV1  and R IV2  are each independently an alkyl group of 1 to 10 carbon atoms, an alkoxyl group of 1 to 10 carbon atoms, an alkenyl group of 2 to 10 carbon atoms, or an alkenyloxy group of 2 to 10 carbon atoms, wherein one or more non-adjacent —CH 2 — groups present in the groups are each independently optionally replaced with —O— or —S—, and one or more hydrogen atoms present in the groups are each independently optionally replaced with a fluorine or chlorine atom); and
 one or more compounds represented by general formula (I): 
 
       
         
           
           
               
               
           
         
       
       (wherein R 1  is a hydrogen atom, —O—, —OH, or an alkyl group of 1 to 12 carbon atoms, wherein one or more —CH 2 — groups present in the alkyl group are each independently optionally replaced with —O—, —S—, —CH═CH—, —C≡C—, —CO—, —CO—O—, —O—CO—, —OCF 2 —, or —CF 2 O—; R 2 , R 3 , R 4 , and R 5  are each independently an alkyl group of 1 to 8 carbon atoms, wherein one or more —CH 2 — groups present in the alkyl group are each independently optionally replaced with —O—, —S—, —CH═CH—, —C≡C—, —CO—, —CO—O—, —O—CO—, —OCF 2 —, or —CF 2 O—, and R 2  and R 3  and/or R 4  and R 5  are optionally taken together to form a ring; R 6  and R 7  are each independently a hydrogen atom or an alkyl group of 1 to 6 carbon atoms, wherein one or more —CH 2 — groups present in the alkyl group are each independently optionally replaced with —O—, —S—, —CH═CH—, —C≡C—, —CO—, —CO—O—, —O—CO—, —OCF 2 —, or —CF 2 O—; n 1  is an integer of 1 to 6, wherein if n 1  is an integer of 2 to 6, each occurrence of R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , and R 7  may be the same or different; and M 1  is a monovalent to hexavalent organic group having a valence equal to n 1 ). 
     
     
         2 . The liquid crystal composition according to  claim 1 , wherein the one or more compounds represented by general formula (I-IV) are selected from compounds represented by general formula (I-IV) wherein R IV1  and R IV2  are each independently an alkenyl group of 2 to 10 carbon atoms or an alkenyloxy group of 2 to 10 carbon atoms. 
     
     
         3 . The liquid crystal composition according to  claim 1 , wherein the one or more compounds represented by general formula (I) comprise two or more compounds represented by general formula (I). 
     
     
         4 . The liquid crystal composition according  claim 1 , further comprising one or more compounds selected from the group consisting of compounds represented by general formulas (LC3) to (LC5): 
       
         
           
           
               
               
           
         
         (wherein R LC31 , R LC32 , R LC41 , R LC42 , R LC51 , and R LC52  are each independently an alkyl group of 1 to 15 carbon atoms or an alkenyl group of 2 to 15 carbon atoms, wherein one or more —CH 2 — groups or two or more non-adjacent —CH 2 — groups in the groups are each independently optionally replaced with —O— or —S—, and one or more hydrogen atoms present in R LC31 , R LC32 , R LC41 , R LC42 , R LC51 , and R LC52  are each independently optionally replaced with a fluorine or chlorine atom; A LC31 , A LC32 , A LC41 , A LC42 , A LC51 , and A LC52  are each independently trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene, 2,3-difluoro-1, 4-phenylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl; Z LC31 , Z LC32 , Z LC41 , Z LC42 , Z LC51 , and Z LC52  are each independently a single bond, —CH═CH—, —C≡C—, —CH 2 CH 2 —, —(CH 2 ) 4 —, —COO—, —OCO—, —OCH 2 —, —CH 2 O—, —OCF 2 —, or —CF 2 O—; Z 5  is —CH 2 — or an oxygen atom; X LC41  is a hydrogen or fluorine atom; and m LC31 , m LC32 , m LC41 , m LC42 , m LC51 , and m LC52  are each independently 0 to 3, wherein m LC31 +m LC32 , m LC41 +m LC42 , and m LC51 +m LC52  are 1, 2, or 3, and each occurrence of A LC31  to A LC52  and Z LC31  to Z LC52  may be the same or different). 
       
     
     
         5 . The liquid crystal composition according to  claim 1 , further comprising one or more compounds represented by general formula (III): 
       
         
           
           
               
               
           
         
         (wherein R 33  and R 34  are each independently an alkyl group of 1 to 15 carbon atoms, wherein one or more —CH 2 — groups in the alkyl group are optionally replaced with —O—, —CH═CH—, —CO—, —OCO—, —COO—, —C≡C—, —CF 2 O—, or —OCF 2 —, with the proviso that no oxygen atoms are directly adjacent to each other, and one or more hydrogen atoms in the alkyl group are optionally replaced with halogen; A 31  to A 33  are each independently trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, 1,4-bicyclo[2.2.2]octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl; Z 31  and Z 32  are each independently a single bond, —CH═CH—, —C≡C—, —CH 2 CH 2 —, —(CH 2 ) 4 —, —OCH 2 —, —CH 2 O—, —OCF 2 —, or —CF 2 O—; and m 31  is 0, 1, or 2, wherein each occurrence of A 31  and Z 31  may be the same or different, with the proviso that compounds represented by general formula (I-IV) are excluded from the compounds represented by general formula (III)). 
       
     
     
         6 . The liquid crystal composition according to  claim 1 , wherein n 1  in general formula (I) is 3. 
     
     
         7 . The liquid crystal composition according to any one of  claims 1  to  6 , wherein the compounds represented by general formula (I-IV) are present in the liquid crystal composition in a total amount of 3% to 70% by mass. 
     
     
         8 . The liquid crystal composition according to  claim 1 , wherein the compounds represented by general formula (I) are present in the liquid crystal composition in an amount of 0.01% to 5% by mass. 
     
     
         9 . The liquid crystal composition according to  claim 4 , wherein the compounds selected from the group consisting of compounds represented by general formulas (LC3) to (LC5) are present in the liquid crystal composition in a total amount of 10% to 90% by mass. 
     
     
         10 . The liquid crystal composition according to  claim 1 , wherein the liquid crystal composition has a dielectric anisotropy (Δ∈) at 25° C. of −2.0 to −8.0, a refractive index anisotropy (Δn) at 20° C. of 0.08 to 0.14, a viscosity (η) at 20° C. of 10 to 30 mPa·s, a rotational viscosity (γ 1 ) at 20° C. of 60 to 130 mPa·s, and a nematic-isotropic liquid phase transition temperature (T ni ) of 60° C. to 120° C. 
     
     
         11 . The liquid crystal composition according to  claim 1 , further comprising one or more polymerizable compounds and/or one or more antioxidants. 
     
     
         12 . A liquid crystal display device comprising the liquid crystal composition according to  claim 1 . 
     
     
         13 . An active-matrix liquid crystal display device comprising the liquid crystal composition according to  claim 1 . 
     
     
         14 . A VA, PSVA, PSA, FFS, ECB, or IPS liquid crystal display device comprising the liquid crystal composition according to  claim 1 .